Oil temps !!??

[stevieturbo]

fastbikes76 said:

That's good to know someone else has fitted a temp gauge, Do you still have the stock one in the dash ? If so how did the two compare ?

Still find it crazy that its taken 7 years to decide this needs some proper investigation as to whether its an issue or not

My LS engine isnt in a Monaro...and not much is standard lol.

[MatrixXXx]

If it is in the sump then it will read accurately just won't be reading the oil temp in the engine, as i have said before we stopped putting oil sensors in the sump for this very reason, especially when the oil bypass valve opens and squirts hot oil on or near the sensor . they are best fitted in the oil gallery in moving oil.

[stevieturbo]

MatrixXXx said:

If it is in the sump then it will read accurately just won't be reading the oil temp in the engine, as i have said before we stopped putting oil sensors in the sump for this very reason, especially when the oil bypass valve opens and squirts hot oil on or near the sensor . they are best fitted in the oil gallery in moving oil.

Oil is moving very rapidly around the engine, and there wouldnt really be any very sudden temperature spikes, plus typical sensors used would have a very slow response time too, maybe a few secodns

So for the few seconds it takes oil to circulate and end up back in the sump, I dont think it would make a huge difference where the sensor is mounted.
Hard to say whether the sump would be deemed a cooler or hotter location.

It could well be hotter, as there is no cooling assistance from the colder engine block once it's in the main galleries.

[MatrixXXx]

MatrixXXx said:

I do a lot of work on control systems for big engines and always have problems with oil temp, the oil can hold the temp and not mix , so you can get clumps of hot oil moving past the senders causing the oil temp to go up and down, so we alter the sampling rate to stabilize the oil temp readings and we never use them as a shutdown as they are not stable enough. water temps on some of the new engines can get up to 130 C as they are pressurized, some of the new cars i have driven don't even show water temp or oil temp any more, as if they showed the real temps everyone would panic.

my point was that when you see the oil temp at 130 c the water temp (on mine )hasn't moved its under a 1/4 of the range still 3/4 to go before it overheats.

As mentioned before the senders are quick to react it is the sampling rate (digital to ECU) that determines the rate of rise, if they are direct to the gauge then they are stabilized by resistors.
A typical sump I work with contains 60 gallons of oil, so they may take more time for the oil to re circulate. but the principle should be the same, the oil can be at different temps in the sump, so its the average temp we want to see.

Its more a case of do you want to see the temp of the oil going in to the pump. out of the pump or out of the engine. the oil is going to come in contact with components far hotter than the coolant is going to circulate around.

[stevieturbo]

From googling, reports seem to suggest typical oil flow in an LS engine would be around 5-6 gpm at higher rpm's ( ie 20 litres per minute or so, 5-6 US gallons )

So the oil is circulating at a very high rate and sump oil getting displaced and replaced at a very high rate baring in mind there is barely 6 litres or so.
So it's fully replaced 3-4 times a minute give or take.

Most typical temperature sensors for fluids in a car are not fast acting. They're cheap, they're reliable...but they are not fast. Simply because they dont need to be.

They wont take minutes of course, but you wouldnt see a rise of say 20degC in 1 second, perhaps maybe 3-4 seconds if there was an extreme temp change in that period.

[stevieturbo]

At a hillclimb today, not particularly conclusive results I think. Approx 47 second hill.

All runs very similar, but these were the 3 timed runs


Run 3,
ECT 79degC and EOT 75degC at start
ECT 78degC and EOT 86degC at finish


Run 4,
ECT 83degC and EOT 83degC at start
ECT 81degC and EOT 94degC at finish

Run 5,
ECT 80degC and EOT 81degC at start
ECT 79degC and EOT 90degC at finish

Of more note, on Thursday I went up for a nosey and got stuck behind some aholes blocking the road for 30mins.

ECT whilst sitting there doing nothing got up to 95degC, but whilst sitting there I had a nosey and noticed oil temp getting as high as 105degC
I guess not a surprise with the oil doing it's job, but also the hot engine causing overall temperatures to be higher.

So if you run the normal hot stat that see's the engine run around 100degC, it would probably be quite normal to see oil temps in the 100-110degC range...under even normal calm driving.

And there is a very good chance temperatures could get quite high under more enthusiastic use.

Edited by stevieturbo on Saturday 23 August 21:04

[fastbikes76]

My adapter arrived today but I discovered my gauges I sold to a mate and then bought back off him have been damaged and no longer works

I have just ordered a new temp gauge so should have results by next weekend on an otherwise stock LS2 engine.

[stevieturbo]

Unless it's around a race track or something..it's very difficult to actually try and drive hard for a test...as it's just too dangerous on the open roads for that for any length of time.

But one things for sure...hot engine = very hot oil.

[fastbikes76]

stevieturbo said:

Unless it's around a race track or something..it's very difficult to actually try and drive hard for a test...as it's just too dangerous on the open roads for that for any length of time.

But one things for sure...hot engine = very hot oil.

I can see 120-130c on a prolonged motorway hoon

[stevieturbo]

fastbikes76 said:

I can see 120-130c on a prolonged motorway hoon

Engine or oil ? and with a decent gauge ?

[fastbikes76]

stevieturbo said:

Engine or oil ? and with a decent gauge ?

Oil, and on the stock gauge. Thats why I'm rigging up a proper gauge to see what the temps actually are.

My adapter arrived today but my gauge is buggered New unit oredered tonight and on the way.

[stigmundfreud]

stevieturbo said:

At a hillclimb today, not particularly conclusive results I think. Approx 47 second hill.

All runs very similar, but these were the 3 timed runs


Run 3,
ECT 79degC and EOT 75degC at start
ECT 78degC and EOT 86degC at finish


Run 4,
ECT 83degC and EOT 83degC at start
ECT 81degC and EOT 94degC at finish

Run 5,
ECT 80degC and EOT 81degC at start
ECT 79degC and EOT 90degC at finish

Of more note, on Thursday I went up for a nosey and got stuck behind some aholes blocking the road for 30mins.

ECT whilst sitting there doing nothing got up to 95degC, but whilst sitting there I had a nosey and noticed oil temp getting as high as 105degC
I guess not a surprise with the oil doing it's job, but also the hot engine causing overall temperatures to be higher.

So if you run the normal hot stat that see's the engine run around 100degC, it would probably be quite normal to see oil temps in the 100-110degC range...under even normal calm driving.

And there is a very good chance temperatures could get quite high under more enthusiastic use.

Edited by stevieturbo on Saturday 23 August 21:04

which is why, I suspect, we have a calculated oil temp pid as the calculation or rather the oil temp to ect along with a few other checks is fairly accurate

[stevieturbo]

I'm amazed the search feature worked to find this !! lol

I did a local sprint yesterday, cool day, lap and a half of the track, circa 2 mins per outing. and I think just shy of 2 miles overall.

Slightly warmer stat fitted as temps outside are getting colder, 86degC stat, and coolant temp typically runs 86-88degC

This also see's oil temp rise by a similar amount from circa 73-75degC to 83-85degC under normal driving.

Start of the lap

ECT around 87degC, max 90degC at end of lap
EOT around 85degC, max 110degC at end of lap

Temperatures through the day were fairly consistent within that range, say 3-4deg deviation at end of lap.
Lap is a good range, mostly 3rd gear but down to 2nd, speeds from as low as 25mph once moving to 145mph over the finish.

I'd imagine if I had a OEM stat running close to 100degC at the start, oil temps could get very hot indeed

My oil pressure isnt great at times, but engine is a few years old now and seen lots of abuse, will probably refresh this winter. Would be hard to say it is directly temperature related though as oil isnt hot enough for it to get as low as it does.
Whether that lower pressure affects overall temps, hard to say.

Certainly in my case, still not enough to warrant an oil cooler

[fastbikes76]

Hi Steve,

Cheers for updating this. I have not forgotten about this but just been really busy with my Jap crap

I just twin turbo'd an Auto that in stock NA form suffers with the box running too hot already. Some research found one of these to fit the stock sump plug thread which is working a treat for monitoring oil temps..

http://www.ebay.co.uk/itm/371141397945?_trksid=p20...

I did originally buy a oil cooler blanking plate from the States with a oil sender adapter for the R8 but as the car had literally just been serviced I wasn't happy with the amount of oil trying to come out when I attempted to fit it.

SO I shall buy a sump plug adapter similar to the link above and go that route as swapping sump plugs quickly can be done with pretty much zero oil loss (as I did with the auto box one). I have a Mitsi I'm breaking with £30k mods alone which has 11 AEM gauges fitted..yes 11 !! SO I can now monitor pretty much everything and anything including moon cycles


Once I have done some tests I will update this thread as to the accuracy of the stock gauge and real world oil temps.

[Gary H 2008]

Mmm...so I'd put money on +10 to +20 indicated through the range...

[fastbikes76]

Gary H 2008 said:

Mmm...so I'd put money on +10 to +20 indicated through the range...

That's the way its looking going from Stevie's post. Roughly 20*c hotter oil temps than coolant temp meaning the gauge readings of 110 normal driving up to 130 spirited driving seems very much a reality !! I still have no confidence in running oil to those sort of temps.

Ive not driven the R8 for weeks now so perhaps I should pull finger and get the plug and sensor fitted to put this speculation to bed. The cooler weather is upon us now so I missed my opportunity but I guess the main thing is comparing what the AEM gauge says VS's the OEM guestimator.

[ARAF]

fastbikes76 said:

Gary H 2008 said:

Mmm...so I'd put money on +10 to +20 indicated through the range...

That's the way its looking going from Stevie's post. Roughly 20*c hotter oil temps than coolant temp meaning the gauge readings of 110 normal driving up to 130 spirited driving seems very much a reality !! I still have no confidence in running oil to those sort of temps.

The cooler weather won't save you, and I really don't like the idea of guessing oil temps when they are so high.

BTW, have you still got my stickers FB, or do I need to get some more - as our oil filter will be changed this week.

[fastbikes76]

ARAF said:

The cooler weather won't save you, and I really don't like the idea of guessing oil temps when they are so high.

BTW, have you still got my stickers FB, or do I need to get some more - as our oil filter will be changed this week.

Yes mate, Still in the arm rest PM me your addy and I will fire them off first class tomorrow.

[ARAF]

fastbikes76 said:

ARAF said:

The cooler weather won't save you, and I really don't like the idea of guessing oil temps when they are so high.

BTW, have you still got my stickers FB, or do I need to get some more - as our oil filter will be changed this week.

Yes mate, Still in the arm rest PM me your addy and I will fire them off first class tomorrow.

A familiar place for them, as that's where I used to leave them. Are you coming to the Christmas dinner, as I could collect them then?

[stevieturbo]

fastbikes76 said:

That's the way its looking going from Stevie's post. Roughly 20*c hotter oil temps than coolant temp meaning the gauge readings of 110 normal driving up to 130 spirited driving seems very much a reality !! I still have no confidence in running oil to those sort of temps.

Pretty much under normal driving EOT will pretty much track ECT. No real surprise there anyway as one is cooling/heating each other at any given time.

As you start to push harder though, there is only so much cooling effect the engine block/sump can offer the oil system and temps will start to rise.

So if you're running factory stats and perhaps in the 100degC region at low loads...hitting 110, 120degC after some hard driving probably isnt too unrealistic.

How long it might take a n/a car, or making lower power I dont know though.

As for swapping sensors about, the typical Bosch Motorsport NTC sensor, M12 fitment can be bought for around £10. I just screw them in and leave them in and if not enough logging channels, just swap wiring about to what I want to log at the time.